Young drivers are more likely to have road accidents because their working memory, essential for spotting hazards, is not fully developed, a new study shows.

The research suggests that development of the adolescent brain may play a critical role in whether a teenager is more likely to crash. Previous studies into why adolescent drivers crash has often focused on driving experience and skills. But working memory, which develops through adolescence into the twenties, is a frontal lobe process associated with complex moment-to-moment tasks and is essential to driving.


In the U.S. study, led by researchers at the Annenberg Public Policy Centre (APPC) of the University of Pennsylvania, scientists found that slower growth in the development of working memory is linked with motor vehicle crashes. The findings suggest cognitive development screening could be a new strategy for identifying and tailoring driving interventions for teens at high risk for crashes.

Study author Dr. Elizabeth Walshe, from the University of Pennsylvania, said: "We found that teens who had slower development in working memory were more likely to report being in a crash.


"Safe driving involves scanning, monitoring, and updating information about the vehicle and environment while managing multiple subtasks and distractors. All of these tasks challenge working memory, especially when a young driver has not yet fully learned to automate many basic driving routines."

When compared with other age groups, adolescent drivers are at higher risk of crashes, injuries and mortality. Poor skills and inexperience explain some of this risk as research shows crash rates are highest during the first six months of independent driving.

But even among equally novice drivers, crash risk is age-graded.


Dr. Walshe said: "Not all young drivers crash. So we thought, what is it about those who are crashing? It could be related to variability in working memory development. Given this age-graded risk, individual variation in development is likely associated with crash risk, but its nature and contribution to this risk is not known."

Existing research shows a link between lower working memory capacity and reckless and inattentive driving, crashes, and poor performance on simulated driving tasks. In their new study, scientists measured the working memory of 118 adolescents year-on-year from aged 11 to 13 and 14 to 16 and again at 18 to 20 years. They then compared links between working memory and the crash outcome of the 84 participants who became drivers and were asked to complete a survey. Drivers were asked about their driving experience, crash history and driving behaviors as well as mobile phone use at the wheel.

Scientists found drivers aged around 17 had a higher crash rate than drivers aged around 20 when beginning to drive independently. But the crash outcome was not associated with the number of years motorists had been driving as results suggest a slower working memory was linked with young driver crashes.

Dr. Walshe said: "The crash outcome was not associated with number of years driving.


"The results demonstrated that the variance in the relative trajectory of working memory growth, but not the baseline (intercepts), was associated with crashes within approximately three years after the start of driving. Adolescents with a divergent trajectory of working memory growth had a greater likelihood of being involved in a crash. The relative variance in the growth trajectory of working memory remained strongly and independently associated with crashes despite controlling for other risk-related factors, such as reckless driving, drug use, and other risk-related traits and behaviors. Furthermore, the model remained robust with the addition of IQ."

Scientists said assessing working memory during adolescence may help to identify at-risk teen drivers and provide interventions such as driving aids or training. Such measures could address limitations in working memory-related skills that are critical for safe driving.

Profesor Flaura Winston, from the APPC, said: "This research points to the fact that crashes are predictable and preventable. It focuses attention more on the role of the driver and the driver's clinician. A clinician could identify teens who will be at an increased risk and use 'precision prevention' to tailor anticipatory guidance so that young drivers achieve independent mobility in a safe way."

Prof. Walshe said precision prevention could provide different types of driver training or a release from driving restrictions at different times based on their development. Results suggest some form of standardized screening or testing during adolescence could determine which teens have slower development of working memory. Prof Winston added: "Ideally, we'd be able to offer interventions like driver training or technologies like in-vehicle alert systems to assist new drivers who need it."

The team do not yet know whether or how working memory development may predict crashes and further research is needed into factors that lead to the different rate of development of working memory to identify high-risk groups.

The study was published today (Fri) in the JAMA Network Open medical journal.